Councils are failing to refer incompetent teachers to General Teaching Council disciplinary hearings, figures disclosed yesterday.

A report revealed that more than half of the local authorities in England – 88 out of 154 – had not referred a single case to the profession's regulatory body. Only 78 cases have been heard in the 10 years since the disciplinary body, which has powers to strike off incompetent teachers, was set up.

This is despite claims made by former government adviser Sir Cyril Taylor and former schools inspector Chris Woodhead that there are up to 20,000 incompetent teachers in schools (the equivalent of 130 per authority). Now the GTC has written to every local council in the country, telling them they and schools must fulfil their legal duty to refer all appropriate cases to the council.

Research commissioned by the Department for Children, Schools and Families revealed "inconsistencies" in the way councils tackled their responsibilities. Some told researchers they were refusing to refer cases because they thought the GTC would be "too lenient". Others claimed that referrals would lead to teachers being removed from the register when their performance could be improved with local help.

Keith Bartley, chief executive of the GTC, also questioned inconsistencies between councils of different sizes. "I don't understand why some quite small authorities have been referring a number of cases whereas some quite large authorities have not forwarded a single case," he said.

Among the authorities that have failed to refer a single case are large counties like Buckinghamshire, Gloucestershire and Hertfordshire, and inner city areas like Hackney, Haringey and Islington. The council with the largest number of referrals is Nottinghamshire, with 14.

The figures show a total of 156 cases have been referred over the 10-year period, with 78 hearings being concluded. Of these, 13 people have been told they can no longer teach, 112 have been suspended, 26 allowed to continue teaching provided they obey conditional registration orders, and six reprimanded. A total of 18 teachers have been cleared.